Humidifier



FIG. 1 is a front perspective view of a humidifier showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof; and,

FIG. 6 is a rear elevation view thereof.

The bottom view forms no part of the claimed design. The subject matter shown in broken lines forms no part of the claimed design. 

The ornamental design for a humidifier, as shown and described. 